assertions for block global state API

All the global state (GS) API functions will check that
qemu_in_main_thread() returns true. If not, it means
that the safety of BQL cannot be guaranteed, and
they need to be moved to I/O.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-5-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/commit.c b/block/commit.c
index b1fc7b9..2ce6637 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -432,6 +432,8 @@
     QEMU_AUTO_VFREE uint8_t *buf = NULL;
     Error *local_err = NULL;
 
+    GLOBAL_STATE_CODE();
+
     if (!drv)
         return -ENOMEDIUM;